Submitted to: American Society of Sugarbeet Technologists
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2005
Publication Date: 7/1/2005
Citation: Smigocki, A.C., Ivic-Haymes, S.D., Boetel, M.A., Campbell, L.G., Dregseth, R.J. 2005. An in vitro sugarbeet root maggot (tetanops myopaeformis) feeding assay. American Society of Sugarbeet Technologists. 33:208-213. Interpretive Summary: The sugarbeet root maggot is considered the most serious pest of sugarbeet in the United States and Canada. Root maggot infestations have spread to over two-thirds of the l.5 million U.S. beet-producing acres and all of the Canadian growing areas. To design effective approaches for control of the root maggot, we developed the first laboratory screening method for root maggot resistance. Laboratory root cultures of root maggot-susceptible and moderately resistant sugarbeet varieties were generated. Using these root cultures, we demonstrated that the root maggot insects moved away from the resistant roots, whereas, they aggregated and fed on the roots of the susceptible variety. This information will be used by scientists for evaluating pesticides and newly developed sugarbeet varieties for root maggot resistance and will lead to the discovery of new sources for insect control.
Technical Abstract: The sugarbeet root maggot (SBRM, Tetanops myopaeformis Röder) is considered the most serious pest of sugarbeet (Beta vulgaris L.) in the United States and Canada. SBRM infestations have spread to over two-thirds of the l.5 million U.S. beet-producing acres and all of the Canadian growing areas. While moderately resistant lines are available, they do not impart complete control. Current control measures rely primarily on chemical insecticides but alternative controls are being sought as the potential for buildup of increased resistance to these pesticides is anticipated. Development of efficient insect bioassays is imperative for rapid screening of resistance resources in order to design effective approaches for control of insect pests. The inability to rear the SBRM insect in the laboratory and a need to utilize mature sugarbeet taproots have hindered the development of a laboratory bioassay for SBRM. We transformed sugarbeet petioles with Agrobacterium rhizogenes and generated hairy root cultures of sugarbeet lines that are either susceptible (F1010) or moderately resistant (F1016) to SBRM. Using these sugarbeet hairy root cultures, as well as the corresponding F1010 and F1016 seedlings, we developed the first in vitro SBRM bioassay. The larvae moved away from the F1016 roots and roamed in a swirling, circular pattern on the surface of the plates. On the F1010 hairy roots, larvae aggregated on the surfaces and burrowed into the root tissues. This bioassay will be used to screen sugarbeet germplasm for resistance to SBRM and to evaluate insecticidal compounds for their ability to control the root maggot.